Abstract
In order to identify monosomic oats, Avena byzantina C. Koch cv. Kanota, intercrosses to produce 40-chromosome hybrids were made between twenty monosomic lines and cytogenetical characteristics of the hybrids were observed. The results of this experiment clearly showed that several monosomics, such as Mk 3, 4, 6, 9, 13 and 22 produced functional 20-chromosome pollen as well as 21-chromosome pollen. All plants with 40 chromosomes were found to be double monosomics which mostly showed 19"+2' chromosome pairing. It was confirmed that monosomic parents which produced double monosomics (Mk 2 and 3; Mk 1, 2, 3, 4 and 8 and 6; Mk 4, 6 and 13 and 9; Mk 1 and 15 and 13; Mk 20 and 22) were deficient for different chromosomes each other. Of 14 kinds of double monosomics obtained from these intercrosses, three which were deficient for a common chromosome 9, such as 4/9, 6/9 and 13/9 showed considerable differences in seed and pollen fertilities and chromosome configurations from each other. Based on the results, it was concluded that Mk 4, 6 and 13 were deficient for functionally different chromosomes each other. These results also indicated that the comparison for various characteristics between double monosomic lines which were deficient for a common chromosome was the effective method for identification of monosomic oats.
